Input device and output detection method in input device

Abstract

The invention provides an input device and an output detection method in the input device which can detect the operation amount of pressing operation with high precision. An input device (100) is provided with: a skin (104) having an operation surface (104A); a first electrode (110) disposed on the rear side of the operation surface; a plurality of second electrodes (120) disposed so as to face the first electrodes; an elastic member (102) disposed between the skin and the plurality of second electrodes; and a control unit (160) that is connected to the plurality of second electrodes and that is configured so that the skin and the elastic member can be elastically deformed by a pressing operation of the operation body (FT) on the operation surface, the control unit selecting at least one second electrode from the plurality of second electrodes as a drive electrode (120Tx). At least one second electrode adjacent to the second electrode selected as the drive electrode is selected from the plurality of second electrodes as a detection electrode (120Rx), a combination of the drive electrode selected from the plurality of second electrodes and the second electrode selected as the detection electrode is switched, and an output of the detection electrode in the plurality of combinations is detected.

Description

Technical Field

[0001] The present disclosure relates to an input device and an output detection method in the input device. Background Art

[0002] Conventionally, there has been a capacitive pressure sensor including: a first electrode sheet having a first electrode layer formed on a first insulating sheet; a second electrode sheet having a second electrode layer formed on a second insulating sheet; an elastomer layer composed of a foamed sheet in which bubbles are dispersed and sandwiched between the first electrode sheet and the second electrode sheet; and adhesive layers respectively formed on the surfaces of the elastomer layer on the first electrode sheet side and the second electrode sheet side. When the first electrode sheet or the second electrode sheet is pressed, the pressing force is detected based on a change in the capacitance between the first electrode layer and the second electrode layer corresponding to a change in the distance between the first electrode layer and the second electrode layer (for example, refer to Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 7091429 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the conventional capacitive pressure sensor, depending on the position where the pressing operation is performed, the positional relationship between the position of the pressing operation and the planes of the first electrode layer and the second electrode layer changes, and thus the amount of change in the capacitance between the first electrode layer and the second electrode layer may vary greatly. When the amounts of change in the capacitance detected depending on the position of the pressing operation are greatly different, the detection accuracy of the operation amount of the pressing operation decreases.

[0008] Therefore, an object of the present invention is to provide an input device and an output detection method in the input device that can detect the operation amount of a pressing operation with high accuracy.

[0009] Means for Solving the Problems

[0010] An input device according to an embodiment of the present disclosure includes: an epidermis having an operation surface; a first electrode disposed on the back side of the operation surface; a plurality of second electrodes disposed opposite to the first electrode; an elastic member disposed between the epidermis and the plurality of second electrodes; and a control unit connected to the plurality of second electrodes. The epidermis and the elastic member can be elastically deformed by a pressing operation of an operation body on the operation surface. The control unit selects at least one second electrode from the plurality of second electrodes as a driving electrode, selects at least one second electrode adjacent to the second electrode selected as the driving electrode from the plurality of second electrodes as a detection electrode, switches the combination of the second electrodes selected as the driving electrode and the detection electrode from the plurality of second electrodes, and detects the output of the detection electrode in the plurality of combinations.

[0011] An output detection method in an input device according to an embodiment of the present disclosure is an output detection method in an input device, and the input device includes: an epidermis having an operation surface; a first electrode disposed on the back side of the operation surface; a plurality of second electrodes disposed opposite to the first electrode; an elastic member disposed between the epidermis and the plurality of second electrodes; and a control unit connected to the plurality of second electrodes. The epidermis and the elastic member can be elastically deformed by a pressing operation of an operation body on the operation surface. The control unit selects at least one second electrode from the plurality of second electrodes as a driving electrode, selects at least one second electrode adjacent to the second electrode selected as the driving electrode from the plurality of second electrodes as a detection electrode, switches the combination of the second electrodes selected as the driving electrode and the detection electrode from the plurality of second electrodes, and detects the output of the detection electrode in the plurality of combinations.

[0012] Advantageous Effects of the Invention

[0013] An input device and an output detection method in an input device that can accurately detect the operation amount of a pressing operation can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing an example of the structure of the input device according to the embodiment.

[0015] Figure 2 It is a view showing an example of a state in which a pressing operation is performed on the input device according to the embodiment.

[0016] Figure 3A It is a view showing an example of the planar structure of a plurality of electrodes.

[0017] Figure 3B It is a view showing an example of a combination of selections of a driving electrode and a detection electrode.

[0018] Figure 3C This is a diagram showing an example of a combination of a drive electrode and a detection electrode for indicating a change based on an eight - fold combination.

[0019] Figure 4 This is a diagram showing an example of the relationship between the pressing force during a pressing operation and the capacitance detected by the detection unit.

[0020] Figure 5A This is a diagram showing an example of a combination of a drive electrode and a detection electrode for a first modification of the embodiment.

[0021] Figure 5B This is a diagram showing an example of a combination of a drive electrode and a detection electrode for a second modification of the embodiment.

[0022] Figure 6A This is a cross - sectional view showing an example of the structure of an input device for a third modification of the embodiment.

[0023] Figure 6B This is a diagram showing an example of the relationship between the pressing force during a pressing operation and the capacitance detected by the detection unit in the input device for the third modification of the embodiment.

[0024] Figure 7A This is a diagram showing an example of a combination of a drive electrode and a detection electrode for a fourth modification of the embodiment.

[0025] Figure 7B This is a diagram showing an example of the structure after further deforming the electrodes of the fourth modification. Detailed Embodiment

[0026] Hereinafter, embodiments of an input device and an output detection method in the input device to which the present disclosure is applied will be described.

[0027] <Embodiment>

[0028] Hereinafter, an XYZ coordinate system will be defined for description. The direction parallel to the X - axis (X - direction), the direction parallel to the Y - axis (Y - direction), and the direction parallel to the Z - axis (Z - direction) are orthogonal to each other. In addition, hereinafter, for the sake of convenience of description, the - Z - direction side may be referred to as the lower side or the bottom, and the + Z - direction side may be referred to as the upper side or the top, but this does not represent a general up - down relationship. In addition, a top view means an observation from the XY plane.

[0029] In addition, hereinafter, in order to easily understand the structure, the lengths, thicknesses, thicknesses, etc. of each part may be exaggeratedly shown. In addition, statements such as parallel and up - down allow deviations to the extent that the effects of the embodiment are not impaired.

[0030] <Embodiment>

[0031] Figure 1This is a cross-sectional view showing an example of the structure of the input device 100 according to an embodiment.

[0032] <Structure of the input device 100>

[0033] The input device 100 includes a substrate 101, a foam layer 102, a skin 104, a floating electrode 110, a plurality of electrodes 120, a drive electrode 120Tx, a detection electrode 120Rx, a power supply 130, a multiplexer 140, a detection unit 150, and an MCU (MicroController Unit, micro control unit) 160. The foam layer 102 is an example of an elastic member that can be deformed by an operator's pressing operation. The upper surface of the skin 104 is the operation surface 104A of the input device 100. The floating electrode 110 is an example of a first electrode. The plurality of electrodes 120 is an example of a plurality of second electrodes, and the drive electrode 120Tx and the detection electrode 120Rx are selected from the plurality of electrodes 120. Therefore, the reference numerals 120 are assigned to the drive electrode 120Tx and the detection electrode 120Rx in parentheses. The MCU 160 is an example of a control unit.

[0034] The input device 100 selects electrodes 120 from the plurality of electrodes 120 provided on the upper surface of the substrate 101 to be used as the drive electrode 120Tx and the detection electrode 120Rx. Regarding such a structure, use Figures 3A to 3B etc. will be described later.

[0035] The input device 100 is a device that determines whether a fingertip FT, which is an example of an operating body, has performed any one of an approach, a touch, or a press operation on the operation surface 104A of the input device 100. The input device 100 determines the presence or absence of an operation in a mutual capacitance method based on the electrostatic capacitance (mutual capacitance) between the drive electrode 120Tx and the detection electrode 120Rx. Hereinafter, an operation based on an approach, a touch, or a press may sometimes be referred to as an approach operation, a touch operation, or a press operation. In addition, the operating body is not limited to the fingertip FT.

[0036] In addition, a press operation is an operation of pressing the operation surface 104A downward with the fingertip FT. A touch operation is an operation in which the fingertip FT contacts the operation surface 104A without pressing downward. An approach operation is an operation in which the fingertip FT does not contact the operation surface 104A, but the closer the fingertip FT approaches the operation surface 104A, the more the electrostatic capacitance between the drive electrode 120Tx and the detection electrode 120Rx increases to a certain extent.

[0037] In addition, when performing an approach operation, a touch operation, and a press operation on the operation surface 104A, the electrostatic capacitance between the drive electrode 120Tx and the detection electrode 120Rx increases in the order of the approach operation, the touch operation, and the press operation. Therefore, the input device 100 can determine the approach operation, the touch operation, and the press operation by using capacitance thresholds for determining the approach operation, the touch operation, and the press operation.

[0038] Hereinafter, the determination methods for the approach operation and the touch operation are omitted, and mainly, the input device 100 that can accurately detect the operation amount of the press operation and the output detection method in the input device will be described.

[0039] In addition, hereinafter, the electrostatic capacitance between the fingertip FT and the floating electrode 110 is set as Cfg, the electrostatic capacitance between the floating electrode 110 and the drive electrode 120Tx is set as Ctf, the electrostatic capacitance between the floating electrode 110 and the detection electrode 120Rx is set as Crf, and the electrostatic capacitance between the drive electrode 120Tx and the detection electrode 120Rx is set as Crt.

[0040] <Substrate 101>

[0041] The substrate 101 is provided at the lower part of the input device 100. As an example, the substrate 101 is a wiring substrate. The drive electrode 120Tx and the detection electrode 120Rx are provided on the upper surface of the substrate 101.

[0042] <Foam layer 102>

[0043] The foam layer 102 has a depth (width) in the Y direction and, as an example, is rectangular in a top view. The foam layer 102 is disposed on the upper surface of the substrate 101. The drive electrode 120Tx and the detection electrode 120Rx are sandwiched between the upper surface of the substrate 101 and the foam layer 102.

[0044] As an example, the foam layer 102 has a shape in which the upper surface and the four side surfaces are continuously curved. The foam layer 102 can be made of a foamed material such as foamed polyurethane, foamed sponge, or foamed rubber and has a buffering property. The foam layer 102 is provided on the substrate 101, and the entire upper surface and the four side surfaces are covered with the skin 104.

[0045] In addition, the foam layer 102 is configured to be thicker than the skin 104. This is because, by making the member that is easily elastically deformed thicker than the skin 104, the tactile sensation perceived by the fingertip FT during the press operation is better. In addition, this is for easily detecting by separating the floating electrode 110 from the drive electrode 120Tx and the detection electrode 120Rx to a certain extent when detecting the press operation using the floating electrode 110, the drive electrode 120Tx, and the detection electrode 120Rx.

[0046] <Epidermis 104>

[0047] The epidermis 104 is a cloth-like cover made of resin, synthetic fiber, synthetic leather, leather, etc., covering the entire outer surface of the foam layer 102 and having a structure whose shape can easily change along the shape of the outer surface of the foam layer 102.

[0048] The epidermis 104 has an operation surface 104A. The operation surface 104A is the upper surface of the epidermis 104 and is a decorative layer exposed to the operator. In addition, a floating electrode 110 is provided at the central portion in the plan view of the lower surface of the epidermis 104. The operation surface 104A is at least a part of the outer surface of the epidermis 104 that overlaps with the floating electrode 110.

[0049] In addition, the epidermis 104 can also be formed of a transparent material together with the floating electrode 110. Transparency refers to the property of transmitting visible light, and the transmittance can be set arbitrarily. In this case, it can also be a structure in which the epidermis 104 and the floating electrode 110 are transparent and the foam layer 102 is visible. For example, the epidermis 104 can be illuminated by setting a light source on the upper surface of the substrate 101 or the like, or a decorative layer can be provided on the lower surface side of the epidermis 104.

[0050] As an example, the epidermis 104 is folded back to the lower surface side of the substrate 101 in a state of covering the upper surface and the side surface of the foam layer 102 and fixed to the lower surface of the substrate 101. In this state, the floating electrode 110 abuts against the outer surface of the foam layer 102.

[0051] In addition, here, a method in which the epidermis 104 is a cloth-like cover and covers the entire outer surface of the foam layer 102 is described, but the epidermis 104 can also be a bag-like cover. In addition, as long as the epidermis 104 is a structure that at least covers the upper surface of the foam layer 102, for example, it can also be a structure that only covers the upper surface of the foam layer 102, or a structure that covers the upper surface and the side surface of the foam layer 102, etc.

[0052] <Floating electrode 110>

[0053] The floating electrode 110 is provided at the central portion in the plan view of the lower surface of the epidermis 104. As an example, the floating electrode 110 is formed by printing silver paste or the like on the lower surface of the epidermis 104. The floating electrode 110 is electrically floating. The floating electrode 110 faces the drive electrode 120Tx and the detection electrode 120Rx and is electromagnetically coupled to the drive electrode 120Tx and the detection electrode 120Rx. In addition, the floating electrode 110 is not limited to printing and can also be formed by vapor deposition on the lower surface of the epidermis 104.

[0054] The floating electrode 110 is provided to mitigate the variation in the output of the detection electrode 120Rx caused by the position of the pressing operation. This is because, by disposing the floating electrode 110 that is electromagnetically coupled to the driving electrode 120Tx and the detection electrode 120Rx on the operation surface 104A side closer than the driving electrode 120Tx and the detection electrode 120Rx, it is possible to mitigate the variation in the output of the detection electrode 120Rx caused by the position of the pressing operation as compared to the case where the floating electrode 110 does not exist. Therefore, it is preferable that the floating electrode 110 has the same size as the plurality of electrodes 120 in a top view, but it may also be smaller or larger than the plurality of electrodes 120. Additionally, in the case where the epidermis 104 is formed of a transparent material, the floating electrode 110 may also be formed of a transparent material.

[0055]

[0056] The plurality of electrodes 120 are disposed at the central portion of the upper surface of the substrate 101 and face the floating electrode 110. As an example, the plurality of electrodes 120 are made of copper foil and are formed by patterning copper foil or the like disposed on the upper surface of the substrate 101.

[0057] The plurality of electrodes 120 are connected to the multiplexer 140 via wirings of the substrate 101, wirings disposed outside the substrate 101, and the like. At least one of the plurality of electrodes 120 is selected as the driving electrode 120Tx, and at least one electrode 120 adjacent to the driving electrode 120Tx is selected as the detection electrode 120Rx. There may be a plurality of driving electrodes 120Tx.

[0058] <driving electrode 120Tx>

[0059] The driving electrode 120Tx is disposed at the central portion of the upper surface of the substrate 101 and faces the floating electrode 110. The driving electrode 120Tx is connected to the power supply 130 via the multiplexer 140.

[0060] <detection electrode 120Rx>

[0061] The detection electrode 120Rx is disposed at the central portion of the upper surface of the substrate 101 and faces the floating electrode 110. The detection electrode 120Rx is connected to the detection unit 150 via the multiplexer 140.

[0062] In addition, since the driving electrode 120Tx and the detection electrode 120Rx are selected from the plurality of electrodes 120 disposed on the upper surface of the substrate 101, among the plurality of electrodes 120, the electrode 120 selected as the driving electrode 120Tx and the electrode 120 selected as the detection electrode 120Rx are switched time-divisionally. Regarding the details thereof, use Figures 3A to 3C and the like will be described later.

[0063] <Power supply 130>

[0064] The power supply 130 is connected between the multiplexer 140 and the MCU 160, and when driven by the control unit 161 of the MCU 160, outputs an alternating drive voltage to the multiplexer 140. The alternating drive voltage is supplied to the drive electrode 120Tx via the multiplexer 140. The power supply 130 may be an AC power supply capable of outputting an alternating drive voltage.

[0065] <Multiplexer 140>

[0066] The multiplexer 140 is connected between the drive electrode 120Tx and the detection electrode 120Rx, and the power supply 130 and the detection unit 150.

[0067] The drive electrode 120Tx and the detection electrode 120Rx are selected from among a plurality of electrodes 120 provided on the upper surface of the substrate 101. In addition, the electrode 120 selected as the drive electrode 120Tx and the electrode 120 selected as the detection electrode 120Rx are switched time-divisionally. Therefore, a multiplexer 140 is provided between the drive electrode 120Tx and the detection electrode 120Rx, and the power supply 130 and the detection unit 150.

[0068] The multiplexer 140 switches the connection state according to the switching signal input from the control unit 161 of the MCU 160 so as to connect the drive electrode 120Tx and the power supply 130, and connect the detection electrode 120Rx and the detection unit 150.

[0069] When the determination unit 162 of the MCU 160 determines whether there is an operation of the fingertip FT, the power supply 130 applies an alternating drive voltage to the drive electrode 120Tx. Therefore, the multiplexer 140 connects the selected drive electrode 120Tx to the power supply 130 according to the switching signal.

[0070] In addition, when the determination unit 162 of the MCU 160 determines whether there is an operation of the fingertip FT, the detection unit 150 detects the output of the detection electrode 120Rx. Therefore, the multiplexer 140 connects the selected detection electrode 120Rx to the detection unit 150 according to the switching signal.

[0071] <Detection unit 150>

[0072] The detection unit 150 is connected to the detection electrode 120Rx via the multiplexer 140, detects the current flowing through the detection electrode 120Rx, and detects the electrostatic capacitance by integrating the current. The detection unit 150 converts the detected electrostatic capacitance into a digital value and outputs it. The detection unit 150 has the function of an AD (Analog to Digital) converter. The detection unit 150 outputs the electrostatic capacitance after digital conversion to the MCU 160.

[0073] <mcu160>

[0074] The MCU 160 has a control unit 161, a determination unit 162, and a memory 163. The MCU 160 is implemented by a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input / output interface, and an internal bus, etc.

[0075] The control unit 161 and the determination unit 162 represent the functions of the program executed by the MCU 160 as function blocks. In addition, the memory 163 functionally represents the memory of the MCU 160.

[0076] The control unit 161 is a processing unit that overall controls the operation of the MCU 160, and for example, drives the power supply 130 and performs other processing.

[0077] While selecting the drive electrode 120Tx and the detection electrode 120Rx, the control unit 161 drives the power supply 130 and outputs a switching signal to the multiplexer 140. In this way, the drive electrode 120Tx and the detection electrode 120Rx are selected from the plurality of electrodes 120, an alternating drive voltage is supplied from the power supply 130 to the drive electrode 120Tx via the multiplexer 140, and the output of the detection electrode 120Rx is detected by the detection unit 150 via the multiplexer 140.

[0078] The determination unit 162 determines whether there is an operation based on the output (capacitance) of the detection unit 150. As an example, the determination unit 162 can determine that any one of approaching, touching, or pressing operations has been performed.

[0079] The memory 163 stores programs, data, etc. required for the control unit 161 and the determination unit 162 to execute processing.

[0080] <Operation of the input device 100>

[0081] Figure 2 is a diagram showing an example of a state in which a pressing operation is performed on the input device 100. When the central portion of the epidermis 104 is pressed downward with the fingertip FT, the epidermis 104, the drive electrode 120Tx, and the foam layer 102 are as Figure 2 When flexed as shown, the distance between the floating electrode 110 and the drive electrode 120Tx and the detection electrode 120Rx becomes shorter. In such a state, the determination unit 162 determines that a pressing operation has been performed. In addition, when the fingertip FT is in contact with the operation surface 104A and not pressed downward, the determination unit 162 determines that a touch operation has been performed. In addition, when the fingertip FT is not in contact with the operation surface 104A but is close and the capacitance between the drive electrode 120Tx and the detection electrode 120Rx has increased to some extent, the determination unit 162 determines that a proximity operation has been performed.

[0082] <Structure of the plurality of electrodes 120>

[0083] Figure 3A It is a diagram showing an example of the planar structure of the plurality of electrodes 120. As an example, the plurality of electrodes 120 are provided at the central portion of the upper surface of the substrate 101.

[0084] The plurality of electrodes 120 as a whole are circular and have a shape that divides the circle into eight equal parts with respect to the center. That is, each electrode 120 has a fan-shaped shape with a central angle of 45 degrees when viewed from above. In this way, if the number of divisions is set to N (N is an integer of 3 or more), the plurality of electrodes 120 are preferably divided into N equal parts when viewed from above. This is because by using the plurality of electrodes 120 with an equally divided shape, the operation position on the operation surface 104A can be appropriately detected.

[0085] As an example, such eight electrodes 120 can be fabricated by dividing a circularly patterned copper foil into eight equal parts with respect to the center. The eight electrodes 120 are separated from each other and are in a non-electrically connected state. The boundary 120A between adjacent electrodes 120 is linear when viewed from above. The boundary 120A is an example of the boundary between adjacent second electrodes. The eight electrodes 120 have eight boundaries 120A.

[0086] In addition, here, a method using eight electrodes 120 that divide a circular electrode into eight equal parts is described, but as long as the plurality of electrodes 120 have the same size and shape, the number of electrodes 120 is not limited to eight, and the overall shape is not limited to a circle. The overall shape of the plurality of electrodes 120 combined can be an ellipse, or can also be a polygon such as a triangle, a quadrilateral, or a pentagon or more.

[0087] <Selected combinations of the drive electrode 120Tx and the detection electrode 120Rx>

[0088] Figure 3B It is a diagram showing an example of the selected combinations of the drive electrode 120Tx and the detection electrode 120Rx. At Figure 3B an example of the selected combinations at times t1, t2, and t3 is shown. In addition, at Figure 3B In the figure, the electrodes 120 selected as the drive electrodes 120Tx are represented by dots, and the electrodes 120 selected as the detection electrodes 120Rx are represented by hollow circles. Additionally, in Figure 3B the substrate 101 is omitted.

[0089] Here, four adjacent electrodes 120 out of the eight electrodes 120 are selected as the drive electrodes 120Tx, and the remaining four adjacent electrodes are selected as the detection electrodes 120Rx. The four drive electrodes 120Tx and the four detection electrodes 120Rx are both arranged in a semi-circular shape.

[0090] An AC drive voltage is supplied from the power supply 130 to the four drive electrodes 120Tx via the multiplexer 140. In addition, the four detection electrodes 120Rx are connected to the detection unit 150 via the multiplexer 140. Therefore, the detection unit 150 detects the capacitance of the four detection electrodes 120Rx.

[0091] In Figure 3B the boundary 120B between the four drive electrodes 120Tx and the four detection electrodes 120Rx is shown surrounded by a dashed ellipse. Here, the boundary between the four drive electrodes 120Tx and the four detection electrodes 120Rx among the eight boundaries 120A of the eight electrodes 120 is distinguished and described as the boundary 120B.

[0092] The boundary 120B between the drive electrode 120Tx and the detection electrode 120Rx is the part where the capacitance Crt can be obtained (refer to Figure 1 ). At the boundary 120B, when the foam layer 102 is flexed due to a pressing operation, the distances between the floating electrode 110 and the drive electrode 120Tx and the detection electrode 120Rx become shorter, and the capacitances Ctf and Crf (refer to Figure 1 ) increase. Since the capacitances Ctf and Crf increase due to the pressing operation, the boundary 120B is the part that gives a large change to the output of the detection electrode 120Rx. That is, the boundary 120B between the drive electrode 120Tx and the detection electrode 120Rx is the part with the highest sensitivity of the output of the detection electrode 120Rx among the eight electrodes 120 when viewed from above. The detection unit 150 detects the capacitance Crt of the boundary 120B.

[0093] The boundary 120B exists on a straight line passing through the center of the eight electrodes 120, so when viewed from above, the output of the detection electrode 120Rx changes according to the position of the pressing operation on the circular area where the eight electrodes 120 are provided. Such a change in the output of the detection electrode 120Rx affects the detection of the operation amount of the pressing operation. The change in the output of the detection electrode 120Rx caused by the position of the pressing operation can be alleviated to some extent by providing the floating electrode 110, but since the output of the detection electrode 120Rx changes according to the positional relationship between the fingertip FT and the driving electrode 120Tx and the detection electrode 120Rx when viewed from above, the alleviation by the floating electrode 110 alone is not sufficient.

[0094] Therefore, the input device 100 of the embodiment shifts the combination of each of the four electrodes 120 selected as the four driving electrodes 120Tx and the four detecting electrodes 120Rx one by one at time t1, t2, and t3, thereby shifting the position of the boundary 120B with high detection sensitivity in a time-sharing manner. The control unit 161 of the MCU 160 selects the combination of each of the four electrodes 120.

[0095] By shifting the boundaries 120B between the driving electrodes 120Tx and the detecting electrodes 120Rx in a time-division manner, the detection sensitivity is equalized in the eight electrodes 120. By equalizing the detection sensitivity of the eight electrodes 120, the operation amount of the pressing operation can be detected with high accuracy.

[0096] Figure 3C 1 is a diagram showing an example of a combination of drive electrodes 120Tx and detection electrodes 120Rx selected based on eight combinations. If the four electrodes 120 selected as the four drive electrodes 120Tx and the four detection electrodes 120Rx are shifted one by one eight times in succession, Figure 3C As in the first to eighth combinations, the four driving electrodes 120Tx and the four detecting electrodes 120Rx rotate one circle. Figure 3B The boundary 120B shown is synonymous with 1 turn.

[0097] For example, in the above-mentioned form, the positions of the boundaries 120B of the four driving electrodes 120Tx and the four detecting electrodes 120Rx are offset, and the operation amount of the pressing operation is detected based on the output of the detecting electrode 120Rx. The operation amount of the pressing operation is the pressing amount of the operating surface 104A, so by detecting the output (electrostatic capacitance) of the detecting electrode 120Rx, the pressing force when the operating surface 104A is pressed can be detected.

[0098] like Figure 3C As shown, by staggering one by one the electrodes 120 selected as the four drive electrodes 120Tx and the four detection electrodes 120Rx and making one full turn, the determination unit 162 of the MCU 160 switches the combination of the electrodes 120 selected as the drive electrodes 120Tx and the detection electrodes 120Rx multiple times so that each of the plurality of electrodes 120 is selected as the detection electrode 120Rx at least once. In addition, the plurality of electrodes 120 have boundaries 120A between multiple adjacent electrodes 120. The MCU 160 switches the combination of the electrodes 120 selected as the drive electrodes 120Tx and the detection electrodes 120Rx multiple times so that the multiple boundaries 120A are each located between the drive electrode 120Tx and the detection electrode 120Rx at least once.

[0099] <Simulation result>

[0100] Figure 4 It is a diagram showing an example of the relationship between the pressing force during a pressing operation in the input device 100 and the capacitance detected by the detection unit 150. Figure 4 It represents the calculation results in the simulation of pressing operations on the central part and the peripheral part of the operation surface 104A. In the simulation, as Figure 3A shown, four drive electrodes 120Tx and four detection electrodes 120Rx are each selected from the eight electrodes 120, and as Figure 3B shown, the electrodes 120 are staggered one by one to make the boundary 120B turn at least once, thereby calculating the capacitance detected by the detection unit 150.

[0101] In addition, the central part of the operation surface 104A is the central part of the eight electrodes 120 when viewed from above, and the peripheral part of the operation surface 104A is the part outside the central part within the circular area of the eight electrodes 120 when viewed from above.

[0102] In addition, in Figure 4 it, the horizontal axis represents the pressing force (N). 0N on the horizontal axis represents the position where the pressing force is zero, indicating the state where the fingertip FT touches the operation surface 104A (the state of a touch operation). In addition, the vertical axis represents the capacitance detected by the detection unit 150 in terms of a count value (unitless). In addition, the characteristics of the pressing operation on the central part of the operation surface 104A are represented by a solid line, and the characteristics of the pressing operation on the peripheral part of the operation surface 104A are represented by a dashed line.

[0103] As Figure 4 As shown, the capacitance of the pressing operation (solid line) on the central portion of the operation surface 104A and the capacitance of the pressing operation (dashed line) on the peripheral portion of the operation surface 104A show very close values. In addition, at approximately 2.5 N, the capacitance starts to increase. A pressing force of 2.5 N is, for example, a relatively weak force of the degree required when operating a button of an electronic device, etc., and is, for example, an appropriate value as the operation load of an operation unit of an electronic device installed in a vehicle interior.

[0104] In addition, in Figure 4 the characteristics shown, when the pressing force is 4 N or less, the counted value of the capacitance is negative, but by detecting the self-capacitance of the detection electrode 120Rx and correcting the mutual capacitance between the driving electrode 120Tx and the detection electrode 120Rx based on the self-capacitance, the counted value of the capacitance can be made substantially zero at a pressing force of 0 N.

[0105] As described above, it can be seen that the capacitance of the pressing operation (solid line) on the central portion of the operation surface 104A and the capacitance of the pressing operation (dashed line) on the peripheral portion of the operation surface 104A show very close values. Thus, it can be confirmed that the input device 100 of the embodiment can accurately detect the operation amount of the pressing operation with high precision regardless of the position of the pressing operation on the operation surface 104A.

[0106] <Effect>

[0107] The input device 100 includes a skin 104 having an operation surface 104A, a first electrode (floating electrode 110) disposed on the back side of the operation surface 104A, a plurality of electrodes 120 disposed opposite to the first electrode (floating electrode 110), a foam layer 102 disposed between the skin 104 and the plurality of electrodes 120, and an MCU 160 connected to the plurality of electrodes 120. The skin 104 and the foam layer 102 can be elastically deformed by the pressing operation of the fingertip FT on the operation surface 104A. The MCU 160 selects at least one electrode 120 from the plurality of electrodes 120 as the driving electrode 120Tx, selects at least one electrode 120 adjacent to the electrode 120 selected as the driving electrode 120Tx from the plurality of electrodes 120 as the detection electrode 120Rx, switches the combination of the electrodes 120 selected as the driving electrode 120Tx and the detection electrode 120Rx from the plurality of electrodes 120, and detects the output of the detection electrode 120Rx in the plurality of combinations.

[0108] Therefore, by detecting the output of the detection electrode 120Rx in the plurality of combinations of the electrodes 120 selected as the driving electrode 120Tx and the detection electrode 120Rx, the output of the detection electrode 120Rx is equalized regardless of the position of the pressing operation on the first electrode (floating electrode 110), the driving electrode 120Tx, and the detection electrode 120Rx.

[0109] Therefore, an input device 100 capable of detecting the operation amount of a pressing operation with high accuracy can be provided.

[0110] In addition, in order to equalize the output of the detection electrode 120Rx regardless of the position of the pressing operation, in addition to the method of switching the combination of the electrodes 120 selected as the drive electrode 120Tx and the detection electrode 120Rx as described above, for example, a method is also considered in which the drive electrode 120Tx and the detection electrode 120Rx have shapes that enter each other in a plan view and the combination is not switched as described above. Even when using the drive electrode 120Tx and the detection electrode 120Rx having shapes that enter each other in a plan view, unevenness in the output of the detection electrode 120Rx due to the position of the pressing operation can be suppressed. However, if the drive electrode 120Tx and the detection electrode 120Rx having shapes that enter each other in a plan view are used, even when a pressing operation is performed, the capacitance (mutual capacitance) does not change sufficiently with respect to the change in the operation amount, and it is difficult to detect the operation amount. Such a phenomenon occurs in the same way in both the case where a pressing operation is performed on the central portion of the operation surface 104A and the case where a pressing operation is performed on the peripheral portion of the operation surface 104A.

[0111] In contrast, the structure of the electrode 120 of the input device 100 according to the embodiment can be simple, the manufacturing cost can be reduced, and in addition, by switching the combination of the electrodes 120 selected as the drive electrode 120Tx and the detection electrode 120Rx, the output of the detection electrode 120Rx can be equalized regardless of the position of the pressing operation. As a result, an input device 100 capable of detecting the operation amount of a pressing operation with high accuracy can be provided.

[0112] Since the first electrode (floating electrode 110) is the floating electrode 110, it does not need to be connected to other detection circuits or the like, and can be formed at low cost.

[0113] In addition, the boundary 120A between adjacent electrodes 120 among the plurality of electrodes 120 is linear in a plan view, so that the capacitor formed between the drive electrode 120Tx and the detection electrode 120Rx can have a simple shape and is easy to manufacture.

[0114] In addition, the MCU160 switches the combination of the electrodes 120 selected as the drive electrode 120Tx and the detection electrode 120Rx multiple times so that each of the plurality of electrodes 120 is selected as the detection electrode 120Rx at least once. By selecting each of the plurality of electrodes 120 as the detection electrode 120Rx at least once, each electrode 120 is surely selected as the detection electrode 120Rx, and the detection accuracy of the pressing operation can be improved.

[0115] In addition, the plurality of electrodes 120 have boundaries 120A between adjacent electrodes 120. The MCU 160 switches the combination of electrodes 120 selected as the drive electrode 120Tx and the detection electrode 120Rx multiple times, so that each of the plurality of boundaries 120A is located between the drive electrode 120Tx and the detection electrode 120Rx at least once. All the boundaries 120A between adjacent electrodes 120 become the boundaries 120B between the drive electrode 120Tx and the detection electrode 120Rx, and all the boundaries 120A are used as the boundaries 120B to detect the capacitance of the detection electrode 120Rx. Therefore, the output of the detection electrode 120Rx can be equalized regardless of the position of the pressing operation, and the detection accuracy of the pressing operation can be improved.

[0116] In addition, when the epidermal layer 104 and the floating electrode 110 are formed of a transparent material, for example, the epidermal layer 104 can be illuminated by providing a light source on the upper surface of the substrate 101 or the like. In addition, a decorative layer can be provided on the lower surface side of the epidermal layer 104.

[0117] In addition, the foaming layer 102 is thicker than the epidermal layer 104, so it flexes smoothly with respect to the pressing operation, and the distance between the floating electrode 110 and the electrode 120 can be appropriately ensured. Therefore, the detection accuracy of the pressing operation can be improved.

[0118] In addition, the plurality of electrodes 120 are equally divided into N (N is an integer of 3 or more) in a plan view. By using the plurality of electrodes 120 having a shape equally divided into N, the operation position with respect to the operation surface 104A can be appropriately detected.

[0119] The output detection method in the input device is an output detection method in an input device, the input device including an epidermal layer 104 having an operation surface 104A, a first electrode (floating electrode 110) disposed on the back side of the operation surface 104A, a plurality of electrodes 120 disposed opposite to the first electrode (floating electrode 110), a foaming layer 102 disposed between the epidermal layer 104 and the plurality of electrodes 120, and an MCU 160 connected to the plurality of electrodes 120. The epidermal layer 104 and the foaming layer 102 can be elastically deformed by the pressing operation of the fingertip FT on the operation surface 104A. The MCU 160 selects at least one electrode 120 from the plurality of electrodes 120 as the drive electrode 120Tx, selects at least one electrode 120 adjacent to the electrode 120 selected as the drive electrode 120Tx from the plurality of electrodes 120 as the detection electrode 120Rx, switches the combination of electrodes 120 selected as the drive electrode 120Tx and the detection electrode 120Rx from the plurality of electrodes 120, and detects the output of the detection electrode 120Rx in the plurality of combinations.

[0120] Therefore, by detecting the output of the detection electrode 120Rx in a plurality of combinations of the electrodes 120 selected as the drive electrode 120Tx and the detection electrode 120Rx, the output of the detection electrode 120Rx is equalized regardless of the position of the pressing operation on the first electrode (floating electrode 110), the drive electrode 120Tx, and the detection electrode 120Rx.

[0121] Therefore, it is possible to provide an output detection method in an input device that can accurately detect the operation amount of a pressing operation.

[0122] <First Modification Example>

[0123] Figure 5A FIG. is an example of a combination of selections of the drive electrode 120Tx and the detection electrode 120Rx showing the first modification example of the embodiment. In Figure 5A it shows, in the same manner as Figure 3C an example of a combination of selections of the drive electrode 120Tx and the detection electrode 120Rx that have been switched eight times.

[0124] In Figure 5A it shows, in the same manner as Figure 3C eight electrodes 120 obtained by equally dividing an electrode that is circular as a whole. In the first modification example, one of the eight electrodes 120 is selected as the drive electrode 120Tx, and the remaining seven are selected as the detection electrodes 120Rx. In this case, the detection electrode 120Rx connected to the detection unit 150 via the multiplexer 140 can be all seven detection electrodes 120Rx, or one or two detection electrodes 120Rx adjacent to the one electrode 120 that is the drive electrode 120Tx.

[0125] By shifting the drive electrode 120Tx one by one eight times, as Figure 5A shown, the combination of the electrodes 120 selected as the drive electrode 120Tx and the detection electrode 120Rx is switched multiple times so that each of the eight electrodes 120 is selected at least once as the detection electrode 120Rx. In addition, the combination of the electrodes 120 selected as the drive electrode 120Tx and the detection electrode 120Rx is switched multiple times so that each of the eight boundaries 120A is located between the drive electrode 120Tx and the detection electrode 120Rx at least once. Therefore, it is possible to provide the input device 100 that can accurately detect the operation amount of a pressing operation.

[0126] <Second Modification Example>

[0127] Figure 5B FIG. is an example of a combination of selections of the drive electrode 120Tx and the detection electrode 120Rx showing the second modification example of the embodiment. In Figure 5B it shows, in the same manner as Figure 3B Similarly, eight electrodes 120 that divide the overall circular electrode into eight equal parts are shown.

[0128] Figure 5B An example of a combination of selections of times t1, t2, and t3 is shown. In addition, in Figure 5B , the electrodes 120 selected as the drive electrodes 120Tx are indicated by dots, and the electrodes 120 selected as the detection electrodes 120Rx are indicated by open circles. In addition, the electrodes 120 maintained at the ground potential are shown in black. Also, in Figure 5B , the substrate 101 is omitted.

[0129] In this way, the electrodes 120 not selected as the drive electrodes 120Tx and the detection electrodes 120Rx can also be used as ground electrodes. In addition, since the drive electrodes 120Tx and the detection electrodes 120Rx on both sides of the ground electrode are far apart and sufficient electrostatic capacitance Crt cannot be obtained at the detection electrode 120Rx (refer to Figure 1 ), the boundary 120B for detecting the electrostatic capacitance Crt by the detection unit 150 becomes the part where the drive electrode 120Tx and the detection electrode 120Rx are adjacent.

[0130] In addition, the electrodes 120 not selected as the drive electrodes 120Tx and the detection electrodes 120Rx are not limited to the ground potential (0V), and can also be maintained at a specified potential (constant potential). By having the electrodes 120 with a constant potential, the operation is stable.

[0131] <Third Modification Example>

[0132] Figure 6A It is a cross-sectional view showing an example of the structure of the input device 100M3 according to the third modification example of the embodiment.

[0133] The input device 100M3 has two foam layers 102A and 102B. The foam layer 102A is an example of an elastic member and an example of a first elastic member. The foam layer 102B is an example of a second elastic member.

[0134] The foam layer 102A divides the Figure 1 foam layer 102 of the input device 100 shown into two layers. In the input device 100M3, the floating electrode 110 is provided on the lower surface of the sheet 110A provided between the foam layers 102A and 102B. The sheet 110A can be a sheet made of resin or the like that can be elastically deformed. As an example, a polyimide sheet can be used. In this case, as an example, the floating electrode 110 can be formed on the lower surface of the polyimide sheet 110A by evaporation plating, printing, or the like.

[0135] In the input device 100M3, similar to Figure 1 As compared with the input device 100 shown, the distance between the floating electrode 110 and the fingertip FT becomes longer. Therefore, the electrostatic capacitance Cfg between the floating electrode 110 and the fingertip FT (refer to Figure 1 ) becomes smaller, further suppressing the variation in the output of the detection electrode 120Rx caused by the position of the pressing operation on the operation surface 104A, and enabling the operation amount of the pressing operation to be detected with high precision.

[0136] In addition, in the input device 100M3, as compared with Figure 1 the input device 100 shown, there is a foam layer 102B directly under the epidermis 104, so the touch feeling when pressing with the fingertip FT is good.

[0137] <Simulation results of Modification 3>

[0138] Figure 6B is a diagram showing an example of the relationship between the pressing force during the pressing operation in the input devices 100 and 100M3 and the electrostatic capacitance detected by the detection unit 150. In the simulation, as Figure 3A shown, four drive electrodes 120Tx and four detection electrodes 120Rx are each selected from the eight electrodes 120. As Figure 3B shown, the electrodes 120 are staggered one by one, and the boundary 120B is rotated at least one week, thereby calculating the electrostatic capacitance detected by the detection unit 150.

[0139] In addition, in Figure 6B , the horizontal axis represents the pressing force (N). 0N on the horizontal axis represents the position where the pressing force is zero, indicating the state where the fingertip FT touches the operation surface 104A (the state of having performed a touch operation). In addition, the vertical axis represents the electrostatic capacitance detected by the detection unit 150 in terms of the count value (unitless). In addition, the characteristics of the pressing operation in the input device 100 are represented by a solid line, and the characteristics of the pressing operation in the input device 100M3 are represented by a dashed line.

[0140] As Figure 6B shown, the electrostatic capacitance of the pressing operation (dashed line) in the input device 100M3 shows a value greater than the electrostatic capacitance of the pressing operation (solid line) in the input device 100. As Figure 6A shown, it is confirmed that by providing the floating electrode 110 between the two foam layers 102A and 102B, the detection sensitivity of the pressing operation increases. Such an increase in the detection sensitivity is the same for both the central part and the peripheral part of the operation surface 104A.

[0141] <Fourth Modification>

[0142] Figure 7A This is a diagram showing an example of a selection combination of the drive electrode 120Tx and the detection electrode 120Rx in the fourth modification of the embodiment. In the fourth modification, the electrode 120 has a structure in which an electrode that is overall square is equally divided into nine grid shapes of 3 rows and 3 columns. Therefore, the shape of each electrode 120 is also square.

[0143] Figure 7A This shows an example of the selection combination in the first to ninth measurements. In addition, in Figure 7A the electrodes 120 selected as the drive electrode 120Tx are indicated by dots, and the electrodes 120 selected as the detection electrode 120Rx are indicated by hollow circles. In addition, in Figure 7A the substrate 101 is omitted.

[0144] Here, a method of selecting one of the nine electrodes 120 as the drive electrode 120Tx and selecting the remaining eight as the detection electrodes 120Rx will be described. Conversely, one of the nine electrodes 120 can be selected as the detection electrode 120Rx and the remaining eight can be selected as the drive electrodes 120Tx.

[0145] An alternating drive voltage is supplied from the power supply 130 to one drive electrode 120Tx via the multiplexer 140. In addition, the eight detection electrodes 120Rx are connected to the detection unit 150 via the multiplexer 140. Therefore, the detection unit 150 detects the electrostatic capacitance of the eight detection electrodes 120Rx. In addition, one or more electrodes 120 adjacent to or surrounding one drive electrode 120Tx can be selected as the detection electrode 120Rx.

[0146] In the first to ninth measurements, by staggering the drive electrode 120Tx one by one, as Figure 7A shown, at least one of the nine electrodes 120 can be selected as the drive electrode 120Tx.

[0147] As Figure 7A shown, the structure in which the square electrodes 120 are arranged is suitable for uniformly detecting a large area. In addition, since the shape of the electrode 120 is simple, there are advantages of being easy to fabricate multiple electrodes 120 and easy to route wires.

[0148] By staggering the boundary 120B between the drive electrode 120Tx and the detection electrode 120Rx in a time-division manner like this, it is possible to equalize the detection sensitivity across the entire nine electrodes 120. By equalizing the detection sensitivity across the entire nine electrodes 120, it is possible to accurately detect the amount of operation of the pressing operation.

[0149] In addition, the nine electrodes 120 shown in Figure 7A can be deformed as shown in Figure 7B . Figure 7B This is a diagram showing an example of a structure in which the electrode 120 of the fourth modification is further modified.

[0150] In Figure 7B , there is a structure in which nine regular hexagonal electrodes 120 are arranged in three rows and three columns like a honeycomb structure. The shape and size of each electrode 120 are the same. As Figure 7B shows, by using a plurality of electrodes 120 arranged in a honeycomb structure, for example, in the first to ninth measurements, by staggering the drive electrodes 120Tx one by one, as Figure 7B shows, at least one of the nine electrodes 120 can be selected as the drive electrode 120Tx.

[0151] As Figure 7B shows, the structure in which the regular hexagonal electrodes 120 are arranged is suitable for uniformly detecting a large area. In addition, since the shape of the electrode 120 is simple, there are advantages of being easy to fabricate a plurality of electrodes 120 and easy to wire.

[0152] In addition, in the fourth modification, a structure in which a plurality of electrodes 120 are arranged in a lattice shape ( Figure 7A ) or a honeycomb shape ( Figure 7B ) has been described, but it is not limited thereto. For example, it can also be arranged in a ring shape. The shape, size, or overall arrangement of each of the plurality of electrodes 120 may be set within the range used for detecting the pressing operation according to the size and shape of the operation surface 104A. By optimizing the shape, size, or overall arrangement of each of the plurality of electrodes 120 in this way, the operation amount of the pressing operation can be detected appropriately and with high precision.

[0153] The input device of the exemplary embodiment of the present disclosure and the output detection method in the input device have been described above. However, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and changes can be made without departing from the claims.

[0154] In addition, this international application claims priority based on Japanese Patent Application No. 2022-200578 filed on December 15, 2022, the entire content of which is incorporated herein by reference.

[0155] Explanation of Reference Numerals

[0156] FT Finger tip (an example of an operating body)

[0157] 100, 100M3 Input device

[0158] 101 Substrate

[0159] 102 Foaming layer (an example of an elastic member)

[0160] 102A Foaming layer (an example of an elastic member, an example of a first elastic member)

[0161] 102B Foaming layer (an example of a second elastic member)

[0162] 104 Epidermis

[0163] 104A Operating surface

[0164] 110 Floating electrode (an example of a first electrode)

[0165] 110A Sheet

[0166] 120 Electrodes (an example of a plurality of second electrodes)

[0167] 120A Boundary (an example of the boundary between adjacent second electrodes)

[0168] 120Tx Driving electrode

[0169] 120Rx Detection electrode

[0170] 130 Power supply

[0171] 140 Multiplexer

[0172] 150 Detection unit

[0173] 160 MCU (an example of a control unit).

Claims

1. An input device, comprising: a skin having an operation surface; a first electrode disposed on the back side of the operation surface; a plurality of second electrodes disposed opposite to the first electrode; an elastic member disposed between the skin and the plurality of second electrodes; and a control unit connected to the plurality of second electrodes, wherein the skin and the elastic member can be elastically deformed by a pressing operation of an operating body on the operation surface, and the control unit performs the following processing: selecting at least one second electrode from the plurality of second electrodes as a driving electrode, selecting at least one second electrode adjacent to the second electrode selected as the driving electrode from the plurality of second electrodes as a detection electrode, switching the combination of the second electrodes selected as the driving electrode and the detection electrode from the plurality of second electrodes, and detecting the output of the detection electrode in the plurality of combinations.

2. The input device according to claim 1, wherein the first electrode is a floating electrode.

3. The input device according to claim 1, wherein the boundaries between adjacent second electrodes among the plurality of second electrodes are linear when viewed from above.

4. The input device according to any one of claims 1 to 3, wherein the control unit switches the combination of the second electrodes selected as the driving electrode and the detection electrode multiple times so that each of the plurality of second electrodes is selected as the detection electrode at least once.

5. The input device according to claim 4, wherein the plurality of second electrodes have boundaries between adjacent second electrodes, and the control unit switches the combination of the second electrodes selected as the driving electrode and the detection electrode multiple times so that each of the plurality of boundaries is located between the driving electrode and the detection electrode at least once.

6. The input device according to claim 4, wherein the control unit maintains at least one of the second electrodes not selected as the driving electrode and the detection electrode among the plurality of second electrodes at a constant potential.

7. The input device according to any one of claims 1 to 6, wherein the skin and the first electrode are formed of a transparent material.

8. The input device according to any one of claims 1 to 7, wherein the elastic member is thicker than the skin.

9. The input device according to any one of claims 1 to 8, wherein the plurality of second electrodes are arranged in a ring shape, a lattice shape or a honeycomb shape when viewed from above.

10. The input device according to claim 9, wherein the plurality of second electrodes are equally divided into N in a top view, where N is an integer of 3 or more.

11. An output detection method, which is an output detection method in an input device, wherein the input device comprises: a skin having an operation surface; a first electrode disposed on the back side of the operation surface; a plurality of second electrodes disposed opposite to the first electrode; an elastic member disposed between the skin and the plurality of second electrodes; and a control unit connected to the plurality of second electrodes, wherein the skin and the elastic member can be elastically deformed by an operator's pressing operation on the operation surface, and the control unit performs the following processing: Select at least one second electrode from the plurality of second electrodes as a driving electrode. Select at least one second electrode adjacent to the second electrode selected as the driving electrode from the plurality of second electrodes as a detection electrode. Switch the combination of the second electrodes selected as the driving electrode and the detection electrode from the plurality of second electrodes, and detect the output of the detection electrode in the plurality of combinations.

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